Wireless and Mobile Networks

Topics, Lecture Notes and References for Study

• Multiple access In a wireless environment: cellular systems, 3G, 4G and beyond
  • Lecture notes: Wireless networks: an introduction
  • Reference: Chapter 6: Mobile and Wireless Networks of Computer Networking : a Top-Down Approach Featuring the Internet by J. Kurose and K. Ross (available on-line)
• Packet radio, Aloha protocol family, CSMA/CA, IEEE 802.11 based wireless local area networks
  • Lecture notes: IEEE 802.11
  • N. Abramson, The AlohaNet - Surfing for Wireless Data
  • Reference: M. Ghast, 802.11 Wireless Networks: The Definitive Guide Chapters 2,3 and 5: Overview of 802.11 networks, the 802.11 MAC and Wired Equivalent Privacy (WEP)
  • The IEEE 802.11 Universe, 802.11 frequency channel map
  • CSIRO's Wireless LAN patent (now worth 200 Million+ dollars)
• Ad hoc and wireless sensor networks
  • Lecture notes: Routing in ad hoc and sensor networks
• Wireless Personal Area Networks (WPANS)
  • Lecture notes: Bluetooth Technology and WPANs
  • References: The Bluetooth Radio System
• Beyond 3G Wireless Networks
  • Lecture notes: Beyond-3G wireless networks
• Internet protocols for next generation mobile networks: Mobile-IPv6

Past Exams

• 2008 exam questions and answers

Packet Radio Experiments and Project

• Programming environment warm-up and Introduction to programming in UNIX/C (These short experiments aim to introduce you the editing-compiling-running-debugging cycle with the freely available tools in the Unix/Linux environment. I think spending a couple of hours on exploring the tutorials below will save you a lot of time when you start doing the experiments and assignments involving programming.)
• Experiments and Assignment: Peer-to-peer chat and reliable file transfer with packet radios
  • About the Packet Radios
    • We use the 2nd generation (USB connected) packet radio boards
    • You can test the boards with this sample packet_radio program (Linux binary, source code is not available, I don't want to give away all the fun :-). Plug in two packet radio boards on two PCs, download the program on both PCs, set as an executable (chmod 700 packet_radio) and run it like this: ./packet_radio /dev/radioXX 9600 (where XX is the number written on the board, we will use these numbers as the unique, 1-byte long board addresses, and 9600 is the bit rate of data transmission).
    • Note:Do not operate the boards closer than 10 cm distance between them, otherwise receivers may get saturated.
  • Supporting Documentation
    • Philips datasheet that has an example of CRC8 and CRC16 implementations (with C source code, see Section 10)
  • Software for the Peer-to-Peer Chat Program
    You need to write an "event-driven" program, i.e., the main() function in your program will do nothing but will wait for some external events to occur. In our case, there are two possibilities: user presses a key to write a message, or wireless radio board receives a character. In Unix systems, one way of writing event driven programs is to use poll() system call. Through the following examples, let's have look at how it works. Please spend a few minutes on studying the following programs before working on your packet radio project (try compiling and running them):
    • The read_keypress.c waits for you to press a key and echoes the character on screen.
    • The listen_radio.c listens the radio device to process received bytes over the wireless medium.
    • If we write a program that waits for any of these two events to occur, we can merge the above examples into a single C program as your starting point: packet_radio.c.
    • Here is the Makefile for compiling the above programs.
  • Software for the Reliable File Transfer Program
    In order to improve the performance of the packet radio to packet radio communications, we have added some symbol encoding trickery into the transmission process, and now provide the packet sending/receiving routines as library functions. In the sample program packet_radio_wlibpr.c you can see how these library routines are used. The program demonstrates the following:
    • How to open a file and read its size (in bytes).
    • Timer usage - this timer is easier to use, and should now be used for waiting for "ACK" packets instead of modifying the timeout of poll().
    • How to send and receive bytes to and from a packet radio using send_packet() and recv_packet() respectively.
    Further information can be found in the README file. To start, you can download the sample program, Makefile, and the required header files and library:
    • packet_radio_wlibpr.c (sample program)
    • pr.h (header file for packet handling library routines)
    • symbols.h (header file for byte encoding routines, they are used by packet handling functions)
    • libpr.a (library of packet handling routines)
    • Makefile (for compiling the sample program into an executable, it creates the executable with the name packet_radio)

Software Tools

I prefer to use freely available software tools especially the GNU ones developed by Free Software Foundation. their Web site has quite extensive documentation, it would be worthwhile exploring the pages. You may also find the below documents useful to refer in printed form:

• C reference card (pdf, 94 KB) (downloaded from http://www.refcard.com)
• UNIX reference card (pdf, 29 KB) (downloaded from http://www.kfa-juelich.de/zam/docs/rfk_e.html)
• Emacs reference card (pdf, 81 KB) (downloaded from http://www.refcard.com)
• GDB reference card (pdf, 80 KB) (downloaded from http://www.refcard.com)

Tutorials

Linux/UNIX tutorial

• UNIX tutorial for beginners

Tutorials on C/C++ programming in the UNIX environment

• Compiling C/C++ programs On UNIX
• Debugging with "gdb"
• Automating program compilation by using Makefiles
• File I/O, file and directory manipulation in UNIX
• UNIX signals programming

Resources on learning, studying, report writing and presentation

• Engineering Faculty teaching and learning resources